1. Field of the Invention
This invention relates generally to color printing; and more particularly to printing different types of color objects (or so-called "copy") in a common printout.
2. Related Art
The use of color monitors for computers has accelerated the need for color printers which can produce a satisfactory printout of what is displayed on the screen. With such equipment, determining what constitutes a "satisfactory" color printout is often quite problematic.
Part of this problem arises from the subjective nature of color. Color is a sensation produced by the combined effects of light, objects and human vision. A particular color or combination of colors may be appealing to one person while at the same time being offensive to another.
Another part of the "satisfactory"-color definitional problem arises from the different color technologies used in computer monitors and color printers. For example, computer monitors are based on a color gamut 202 (FIG. 10) of red, green and blue pixels (RGB) whereas color printers such as inkjet printers are typically based on a color gamut 203 of cyan, magenta, yellow and black (CMYK). The RGB color components of computer monitors are combined together in an "additive" way by mixing red, green and blue light rays to form a first variety 202 of different colors; but the CMYK components of color inks are applied to media in different combinations in a "subtractive" way to form a second variety 203 of different colors.
The mutually overlapping character of the two gamuts 202 and 203 compounds the difficulty of defining what is "satisfactory": a great range of vivid colors 205 which a monitor screen can display are physically unprintable. Equally troublesome, a considerable range of vivid colors 204 which a printer can print tend never to be called up, because they are physically undisplayable by the monitor.
Various different color-management techniques have been used to provide some form of matching between, for instance, the colors viewed on a computer monitor and the colors printed by a specific printer using a given ink formula on a particular type of printing medium. Such color-management techniques have also employed different types of halftoning algorithms (in this art commonly called "rendition" or sometimes "rendering") to improve appearance of color printout of various types of objects (or in traditional publications jargon "copy").
Desktop publishing software has created an additional dimension of the satisfactory-color-definition problem by printing together, in a composite document, objects (or "copy") of different types. Such types include photos and photograph-like images, business graphics (e.g., charts and logos), and scalable text in both color and black.
On one hand, by skewing the printer color output to ensure satisfactory color printing of photos, color-management systems often cause the business graphics in the same document to appear washed out and lose their impact. On the other hand, by skewing the color output to ensure satisfactory color printing of saturated vivid colors for business graphics, color systems can cause a photo in the same document to lose its lifelike appearance.
Some parts of the aforementioned color printing problem have been partially solved by providing manually controlled printer settings to optimize results. In addition, sophisticated users who demand exact color matching from screen to printout can obtain some solutions by customizing object specifications before incorporation into a document--using color-management software integrated into computer operating systems, as well as color-management software supplied as third-party software applications.
Also, some color-matching technology has been incorporated into printer drivers. A driver provides a translation interface from a particular computer operating system, and/or application software running in the computer, to a color printer which acts as a hardcopy output device.
These modern developments, however, have only exacerbated the satisfactory-color problem for another group of users. Those are users who haven't time or interest for making multiple manual selections, or haven't sophistication for setting up exact desired on-screen color for matching by a printout.
There is thus a need for a refined color-management technology which somehow accommodates users of a wide variety of commitment, interest and abilities. Such technology must at the same time overcome the inconsistent color requirements, within a single composite document, of different types of objects or "copy" such as photo images, business graphics, color text, and black text.
As can now be seen, important aspects of the technology which is used in the field of the invention are amenable to useful refinement.